Lubricant



h Patented 17, 1931 UNITED STATES PATENT orrlca DANIELE. BARNABD, FW'HITING, INDIANA, ASSIGNOR TO STANDARD OIL COMPANY,

- OF WHITIN G, INDIILAIN'A, A CORPORATION OF INDIANA LUBRICANT NoDrawing.

- r This invention relates to lubricants and particularly to lubricantsfor aeroplane motors. s

According to the invention the lubricant consists of a base oflubricating oil, together with a relatively small amount of a relativeyhigh volatile and substantially uninflammable diluent. 1

The lubricating oil may be of viscosity and lubricating propertiessuitable for any particular type of engine unden operating conditions.As thevolatile and uninflammable or relatively uninflammable diluent,itis preferred to employ carbon tetrachloride, but it 1 is within thescope of the. invention to use chloroform or other suitable halogensubstituted hydrocarbons, or a mixture of these with relativelysmallquantities of volatile hydrocarbons.

The lubricant may suitably consist of about 90% to 95% of hydrocarbonlubricating oil and 10% to 5% of volatile, uninflammable diluent. Foruse as an aeroplane oil in cold weather, the viscosity of the mixturemay suitably be between 60 and 80 seconds Saybolt at 210 F. and lessthan 100,000 seconds Saybolt at F.

The diluent should be of such a volatility that it is substantiallycompletely eliminated after full-load operation of the engine for aboutone hour or for a considerably shorter time especially where the diluentis uninflammable to a high degree. In general, a product boiling below250 F. will have the desired degree-of volatility.

By way of example, the following composition is given:

Lubricating oil 7 seconds Saybolt viscosity at 100 F., pour at 10 F 93%Carbon tetrachloride 7% The mixture has a viscosity of 85,000 secondsSaybolt at -2() F. and 400 seconds Saybolt at 100 F. The diluent issubstantially completely eliminated after half an hour full-loadoperation of the engine so that the oil increases in viscosity to 730seconds Saybolt at 100 F. and 65 seconds Saybolt at 210 R, which insuressatisfactory lubrica- Applicat ion filed October 19, 1927. Serial No.227,364.

tion for the engine undefi operating conditions.

- The improved lubricant is particularly suitable for use in startingaeroplanes in very cold weather, since it insures oil circulation andlubrication when starting the engine and since the diluent is eliminatedin a relatively short time, eflicient lubrication is insured duringprblonged operation. Moreover, danger of explosion in the crank-case isavoided by the selection of a non-inflammable diluent. The use of ahydrocarbon sufliciently volatile to behave in a similar manner resultsin a very low flash test for the oil, making it rather unsafe to handleand store.

The oil may be prepared by mixing the ingredients before supplying theoil to the engine, or, if desired, the appropriate amount of diluent maybe supplied to the oil in the crank-case. The latter method isparticularly suitable where the aeroplane has been operated for sometime so that the diluent has been eliminatedand then the engine stoppedand allowed to become cold.

Although the invention has been described in connection with the detailsof a specific example thereof, it must be understood that it isnot'intended to be limited thereto, except insofar as included in theaccompanying claims.

I claim:

1. A lubricant for internal combustion engines comprising a fluidlubricating oil and a relatively volatile and substantiallyuninflammable diluent.

2. A lubricant for internal combustion engines comprising a lubricatingoil of characteristics suitable for the effective lubrication of theengine under operating conditions and a relatively small amountofavolatile substantially uninflammable diluent.

3. A lubricant for internal combustion engines comprising hydrocarbonlubricating oil and a halogen substituted hydrocarbon boiling mainlybelow 250 F.

4. A diluted lubricant comprising a mineral lubricating oil and a chloroderivative of a hydrocarbon boiling mainly below 250.

5. A diluted lubricant comprising a mineral lubricating oil and carbontetrachloride.

'6. A lubricant for internal combustion engines comprising to oflubricating oil, and 10% to 5% of a halogen substituted hydrocarbon.

7 A lubricant for internal combustion engines comprising 90% to 95% oflubricating oil, and 10% to 5% of carbon tetrachloride.

8. A lubricant for internal combustion engines comprising 90% to 95% oflubricating oil, and 10% to 5% of carbon tetrachloride, and having aviscosity between 60 and 80 seconds Saybolt at 210 F. and less than100,000 seconds Saybolt at 20 F.

9. A lubricant for internal combustion engines comprising 93% of alubricating oil having a viscosity of about 7 30 seconds sa bolt at F.and a pour of about 10 F., and about 7% of carbon tetrachloride.

10. A lubricant forinternal combustion engines constituted mainly byhydrocarbon mineral lubricating oil of viscosity and lubrieatingproperties suitable for the engine underoperating conditions and notmore than 10% of a readily volatile ,and substantially uninflljammablediluent boiling mainly below 250 11. A lubricant for internal combustionengines comprising a lubricating oil of characteristics suitable for theeffective lubrication of the engine under operating conditions and arelatively small amount of a substantially non-inflammable diluentboiling mainly below 250 F.

In witness whereof, I have hereunto set my hand this 13th day ofOctober, 1927.

' DANIEL P. BARNARD.

